KVM: remove CONFIG_HAVE_KVM_EVENTFD

virt/kvm/eventfd.c is compiled unconditionally, meaning that the ioeventfds
member of struct kvm is accessed unconditionally.  CONFIG_HAVE_KVM_EVENTFD
therefore must be defined for KVM common code to compile successfully,
remove it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/arm64/kvm/Kconfig

@@ -29,7 +29,6 @@ menuconfig KVM
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select KVM_XFER_TO_GUEST_WORK
 	select KVM_VFIO
-	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_IRQFD
 	select HAVE_KVM_DIRTY_RING_ACQ_REL
 	select NEED_KVM_DIRTY_RING_WITH_BITMAP

arch/loongarch/kvm/Kconfig

@@ -22,7 +22,6 @@ config KVM
 	depends on AS_HAS_LVZ_EXTENSION
 	depends on HAVE_KVM
 	select HAVE_KVM_DIRTY_RING_ACQ_REL
-	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_VCPU_ASYNC_IOCTL
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select KVM_GENERIC_HARDWARE_ENABLING

arch/mips/kvm/Kconfig

@@ -22,7 +22,6 @@ config KVM
 	select EXPORT_UASM
 	select PREEMPT_NOTIFIERS
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
-	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_VCPU_ASYNC_IOCTL
 	select KVM_MMIO
 	select KVM_GENERIC_MMU_NOTIFIER

arch/powerpc/kvm/Kconfig

@@ -20,7 +20,6 @@ if VIRTUALIZATION
 config KVM
 	bool
 	select PREEMPT_NOTIFIERS
-	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_VCPU_ASYNC_IOCTL
 	select KVM_VFIO
 	select IRQ_BYPASS_MANAGER

arch/riscv/kvm/Kconfig

@@ -20,7 +20,6 @@ if VIRTUALIZATION
 config KVM
 	tristate "Kernel-based Virtual Machine (KVM) support (EXPERIMENTAL)"
 	depends on RISCV_SBI && MMU
-	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQFD
 	select HAVE_KVM_IRQ_ROUTING

arch/s390/kvm/Kconfig

@@ -23,7 +23,6 @@ config KVM
 	select PREEMPT_NOTIFIERS
 	select HAVE_KVM_CPU_RELAX_INTERCEPT
 	select HAVE_KVM_VCPU_ASYNC_IOCTL
-	select HAVE_KVM_EVENTFD
 	select KVM_ASYNC_PF
 	select KVM_ASYNC_PF_SYNC
 	select HAVE_KVM_IRQCHIP

arch/x86/kvm/Kconfig

@@ -33,7 +33,6 @@ config KVM
 	select IRQ_BYPASS_MANAGER
 	select HAVE_KVM_IRQ_BYPASS
 	select HAVE_KVM_IRQ_ROUTING
-	select HAVE_KVM_EVENTFD
 	select KVM_ASYNC_PF
 	select USER_RETURN_NOTIFIER
 	select KVM_MMIO

include/linux/kvm_host.h

@@ -782,7 +782,6 @@ struct kvm {
 	struct list_head vm_list;
 	struct mutex lock;
 	struct kvm_io_bus __rcu *buses[KVM_NR_BUSES];
-#ifdef CONFIG_HAVE_KVM_EVENTFD
 	struct {
 		spinlock_t        lock;
 		struct list_head  items;
@@ -791,7 +790,6 @@ struct kvm {
 		struct mutex      resampler_lock;
 	} irqfds;
 	struct list_head ioeventfds;
-#endif
 	struct kvm_vm_stat stat;
 	struct kvm_arch arch;
 	refcount_t users_count;
@@ -2056,8 +2054,6 @@ static inline void kvm_free_irq_routing(struct kvm *kvm) {}
 
 int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi);
 
-#ifdef CONFIG_HAVE_KVM_EVENTFD
-
 void kvm_eventfd_init(struct kvm *kvm);
 int kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args);
 
@@ -2082,31 +2078,7 @@ static inline bool kvm_notify_irqfd_resampler(struct kvm *kvm,
 {
 	return false;
 }
-#endif
-
-#else
-
-static inline void kvm_eventfd_init(struct kvm *kvm) {}
-
-static inline int kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
-{
-	return -EINVAL;
-}
-
-static inline void kvm_irqfd_release(struct kvm *kvm) {}
-
-#ifdef CONFIG_HAVE_KVM_IRQCHIP
-static inline void kvm_irq_routing_update(struct kvm *kvm)
-{
-}
-#endif
-
-static inline int kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
-{
-	return -ENOSYS;
-}
-
-#endif /* CONFIG_HAVE_KVM_EVENTFD */
+#endif /* CONFIG_HAVE_KVM_IRQFD */
 
 void kvm_arch_irq_routing_update(struct kvm *kvm);
 

virt/kvm/Kconfig

@@ -3,6 +3,7 @@
 
 config HAVE_KVM
        bool
+       select EVENTFD
 
 config HAVE_KVM_PFNCACHE
        bool
@@ -39,10 +40,6 @@ config NEED_KVM_DIRTY_RING_WITH_BITMAP
 	bool
 	depends on HAVE_KVM_DIRTY_RING
 
-config HAVE_KVM_EVENTFD
-       bool
-       select EVENTFD
-
 config KVM_MMIO
        bool